The present disclosure relates to loading two or more separate layers of particles, for example adsorbent particles, of different composition and/or granulometry into “radial flow” vessels. Radial flow vessels are used in a number of different processes, most notably processes employing thermal swing adsorption (TSA), pressure swing adsorption (PSA), vacuum swing adsorption (VSA), or vacuum-pressure swing adsorption (VPSA) processes for the separation of components of a fluid, for example, oxygen or nitrogen from air. Radial flow vessels may also be used for reactors containing two or more separate layers of catalyst particles.
In any adsorption vessel, it is often desirable to load different types of adsorbent onto various areas of the adsorbent bed of a vessel to remove or treat different components of a fluid as the fluid passes through the bed of adsorbent. In an axial flow vessel, this involves placing the adsorbents in the vessel in horizontal layers, which is easily accomplished. In a radial flow vessel (i.e. in a vessel where the fluid to be processed flows radially (typically radially inward) through the adsorbent bed), this particle loading is more difficult because in radial flow vessels the particle layers are radially disposed and the interface between the particle layers is oriented parallel with gravity.
Industry desires convenient and cost-effective solutions to the problem of loading vessels (especially large vessels) with two or more distinct, concentric, radially disposed layers of particles. There is a particular need in the field of air separation where large vessels holding adsorbent particles are employed to remove carbon dioxide and water from air prior to further processing by cryogenic distillation. There is a particular need in the field of air separation where large vessels holding adsorbent particles are employed to separate oxygen or nitrogen from air in various adsorption processes. Such processes are particularly sensitive to cost considerations. In such processes, there is an ever-present need for reducing capital, and/or operating costs with a view towards lowering overall cost without compromising product quality, notably purity.
Industry desires to conduct the vessel filling operation at an adequate speed by simultaneously filling the vessel with both (or all) particle types and continuing the filling operation substantially without interruption.
Industry desires a particle loading assembly and method to form radially disposed particle layers without screens or other barriers disposed between the particle layers. Such screens or barriers can help segregate the particle layers during loading, but add to the capital cost of the vessel and are useless or harmful to the efficiency of the operation which the filled vessel is designed to perform.
Industry desires a particle loading assembly and method that provides a uniform and high packing density of particles throughout both (or all) particle layers in the vessel.
Industry desires a particle loading assembly and method that achieves a clean (vertical) and not a jagged interface between adjacent particle layers.
Industry desires a particle loading assembly and method that achieves a sharp interface, i.e. a narrow width of an interfacial zone containing particles from both particle layers.
Related disclosures include U.S. Pat. Nos. 3,620,685, 3,972,686, 4,159,785, 4,541,851, 4,698,072, 5,232,479, 5,324,159, 5,819,820, 5,836,362, 5,837,021, 5,931,980, 5,964,259, 6,276,408, 6,866,075, 8,101,133, EP 3,061,514, and WO 99/20384, each incorporated by reference in their entirety with the proviso that, in case of conflict, the present specification governs.